All I know is if you have the Thai Embassy stamp, the next step is to go to the Department of Consular Affairs in the Ministry of Foreign Affairs in Chaengwattana to get them certified in Thailand. Go before 10am to get them back at 2pm.
Here is a map:
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I’ve done it many times for my family’s documents.
I messaged my landlord and told him the law before I landed. He read it, I sent him copies of the pages of my passport, he went to immigration and submitted tm30, sent me the receipt by LINE, then I went with a filled in tm28, to which the officer saw the receipt from the landlord and said why are you here?
He gave me back my stuff and told me it’s all already done.